EP4175137A1 - Rotor for a dynamoelectric rotary machine - Google Patents

Abstract

The invention relates to a rotor (21) for a dynamo-electric rotary machine (23), in particular an asynchronous machine, with a rotor core (24) and a squirrel-cage cage, the squirrel-cage cage having a plurality of electrically conductive cage bars (3) and electrically conductive short-circuit rings (2). , wherein the cage bars (3) are arranged in grooves of the rotor core (24), the cage bars (3) being connected to at least one short-circuit ring (2), the cage bars (3) having a notched area (311).

Description

High mechanical stresses, for example due to notch effects and the associated material fatigue, often occur in rotors for asynchronous machines.

Frequently, those points of a squirrel cage are affected in which the cage bars engage in openings of the squirrel cage ring.

Material fatigue can be delayed by limiting the speed. However, this severely limits the areas of application.

The object of the invention is to reduce or avoid mechanical stresses.

The object is achieved by claim 1, i.e. a rotor for a dynamoelectric rotary machine, in particular an asynchronous machine, with a rotor stack and a squirrel cage, the squirrel cage having a plurality of electrically conductive cage bars and electrically conductive short-circuit rings, the squirrel cage bars in slots of the rotor stack are arranged, wherein the cage bars are connected to at least one short-circuit ring, wherein the cage bars have a notched area.

A short-circuit ring is advantageously attached to a front axial end as well as to a rear axial end of the rotor stack.

The invention is particularly well suited for rotors in which the cage bars and short-circuit ring are connected by laser welding and/or by electron beam welding. Here, the short-circuit ring is welded to the cage bars, preferably radially from the outside. However, others are also suitable for connecting the cage bar and short-circuit ring Processes that enable a material connection.

An embodiment is advantageous in which the notched area lies in an opening of the short-circuit ring. A groove base diameter in the short-circuit ring can thus be increased.

Viewed radially, the short-circuit ring can have more material and thus be more stable. There is less tension.

Mechanical stresses, particularly in the short-circuit ring, are significantly reduced by the design described.

An embodiment is advantageous in which a transition from the notched area to another area of the cage bar has a rounding.

This has the advantage that stress on the cage bar is kept low.

An embodiment is particularly advantageous here, according to which a transition from the notched area to the other area is arcuate or in the shape of a segment of a circle.

A combination of several forms is also conceivable.

A curved or circular segment design ensures an even distribution of stress, especially in the area of this transition.

Also advantageous is an embodiment according to which one end of the notched area lies in one plane with one end of the short-circuit ring.

For example, viewed in the radial direction, the notched area can have a smaller diameter than the remaining area of the cage bar.

An embodiment according to which the transition is in the area of the rotor stack is advantageous.

The notched area can also be referred to as a notched area.

The term notch describes a local removal of cross-sectional parts of a component. However, a notch can also mean that external cross-sectional parts of the component are not present from the start.

This is shown in more detail in the figures.

The invention offers the advantage that no speed limitation is necessary. High speeds can be achieved.

The mechanical stresses in the short-circuit ring, in particular in openings in the short-circuit ring, can be significantly reduced, and a notch effect is reduced. The rotor is suitable for many load cycles that exceed 100,000 cycles, since there is no risk of material fatigue and there is no risk of a connection point between the cage bar and the short-circuit ring breaking.

An operational stability of the rotor can be ensured because a reduction in the mechanical stresses, in particular in the short-circuit ring, in particular in the base of the slot, is reduced.

• Bereitstellen des Rotorpakets,
• Einfügen von Käfigstäben in die axial verlaufenden Öffnungen des Rotorpakets,
• Anbringen wenigstens einer Kurzschlussringscheibe auf aus dem Rotorpaket herausragende Käfigstäbe,
• stoffschlüssiges Verbinden, insbesondere mittels Schweißens der Kurzschlussringscheibe mit den Käfigstäben oder
• Anbringen wenigstens einer weiteren Kurzschlussringscheibe und stoffschlüssiges Verbinden, insbesondere mittels Schweißens der Kurzschlussringscheibe miteinander und mit den Käfigstäben.

The object is also achieved by a method for producing a rotor with the following steps:

• providing the rotor package,
• inserting cage bars into the axially extending openings of the rotor stack,
• Attaching at least one short-circuit ring disk to cage bars protruding from the rotor stack,
• material connection, in particular by means of welding the short-circuit ring disc to the cage bars or
• Attaching at least one further short-circuit ring disk and cohesive connection, in particular by means of welding the short-circuit ring disks to one another and to the cage bars.

The method is explained in more detail in the description of the figures.

The object is also achieved by a cage bar for a rotor and by a dynamo-electric rotary machine having such a rotor.

The described cage bars with the notched area are particularly well suited for a short-circuit ring having a plurality of axially extending openings, the openings being arranged at least substantially around a center point, with at least one radial end of the opening having an elliptically shaped section.

The elliptically shaped section advantageously has an elliptical ratio of height to width which is between 0.2:1 and 0.6:1.

In addition, the shorting ring may have at least one circular section adjacent to the elliptical section.

The circular section has advantages in terms of production, since the openings in the short-circuit ring are formed, for example, by means of a milling cutter, and the circular section has a radius which advantageously resembles a radius of a milling tool.

The short-circuit ring can have several short-circuit ring disks.

The short-circuit ring disks are preferably connected to one another in a materially bonded manner. The material connection is z. B. by welding, advantageously carried out when the cage bars are also present in the openings, so that an integral connection of short-circuit ring disks with each other as well as with the cage bars can be achieved.

FIG 1

einen Schnitt entlang einer Rotationsachse durch einen Rotor einer elektrischen Maschine,

FIG 2

Abbildung mechanischer Spannungen aus FIG 1,

FIG 3

einen Schnitt entlang einer Rotationsachse durch einen Rotor einer dynamoelektrischen rotatorischen Maschine,

FIG 4

Abbildung mechanischer Spannungen aus FIG 3,

FIG 5

den Rotor mit Öffnungen,

FIG 6

die in FIG 5 offenbarte Öffnung im Detail.

FIG 7

den Rotor,

FIG 8

die dynamoelektrische rotatorische Maschine

FIG 9

ein Verfahren zur Herstellung des Rotors.

The invention is described and explained in more detail below with reference to the exemplary embodiments illustrated in the figures. Show it:

FIG 1

a section along an axis of rotation through a rotor of an electrical machine,

FIG 2

Mapping of mechanical stresses FIG 1 ,

3

a section along an axis of rotation through a rotor of a dynamo-electric rotary machine,

FIG 4

Mapping of mechanical stresses 3 ,

5

the rotor with openings,

6

in the 5 disclosed opening in detail.

FIG 7

the rotor,

8

the dynamo-electric rotary machine

9

a method of manufacturing the rotor.

FIG 1 shows a section along an axis of rotation through a rotor of an electrical machine.

The figure shows a cage bar 103, a laminated core 24 and a shaft 25.

In the figure, the cage bar 103 is connected to short-circuit ring disks 4 , 41 , 42 , 43 , 44 , 45 by means of weld seams 46 .

The short-circuit rings 4, ...,45 form a short-circuit ring 2 in the figure.

A rotor advantageously has a plurality of cage bars 103 , with the cage bars 103 forming a squirrel-cage cage with the short-circuit ring 2 .

In FIG 2 it can be seen that through the in figure 1 shown embodiment mechanical stresses, especially in the short-circuit ring 2 arise.

It will therefore be the in 3 shown embodiment proposed.

3 shows a section along an axis of rotation through a rotor of a dynamo-electric rotary machine.

The figure shows a shaft 25 and a laminated core 24 .

The notched area 311 (can also be called the area with a notch) is in the figure in an opening of the short-circuit ring 2, the short-circuit ring 2 also being formed in this figure by a plurality of short-circuit ring disks 4,...,45.

The squirrel-cage cage, ie a plurality of electrically conductive cage bars 3 and at least one electrically conductive short-circuit ring 2, preferably two electrically conductive short-circuit rings 2, are advantageously part of an asynchronous machine.

All cage bars 3 advantageously have a notched area 311 .

In this embodiment, too, an electrical or mechanical connection of annular short-circuit disks 4, . . .

In the 3 The embodiment shown offers many advantages, for example in FIG 4 that hardly any mechanical stresses occur, especially in the area of openings of the short-circuit ring disks 4, ...,45.

The mechanical stresses and loads are in FIG 2 and FIG 4 recognizable by the dark shades. The darker the shade, the higher the mechanical stress at that point.

Dynamoelectric rotary machines designed in this way can achieve high speeds without fear of material fatigue.

the inside 3 The transition area 310 shown advantageously has a rounding, so a stress on the cage bar 3 can be kept low in this area.

An arcuate transition or a transition in the shape of a segment of a circle is advantageous. The figure also shows that the end of the notched portion 311 is coplanar with one end of the shorting ring 2 .

The short-circuit ring disks 4, ..., 45 are at least partially bonded to one another.

5 shows the rotor 21 in a view in which a section has been made through the cage bar 3 and also through an opening 11 of the short-circuit ring or the individual short-circuit ring disks.

In the figure, the short-circuit ring 2 is formed purely by way of example from six short-circuit ring disks 4, . . . , 45.

The cage bars 3 are arranged in a rotor core 24 and protrude from it.

The cage bars 3 are advantageously prefabricated cage bars.

A stable connection is achieved by integrally connecting, in particular by means of welding, the short-circuit ring disks 4, ..., 45 to the cage bars 3 or by integrally connecting, in particular by means of welding, several short-circuit ring disks 4, ..., 45 to one another and to the cage bars 3 that can withstand high speeds.

The short-circuit ring disks 4, ..., 45 can have shape deviations, for example to form a trough so that welding material can be introduced.

The short-circuit ring 2 rests on the shaft 25 in the figure.

The figure shows that the short-circuit ring has a plurality of openings 11 running axially.

Advantageously, these openings 11 are at least substantially arranged around a center point M and have an elliptically shaped section.

This will in 6 explained in more detail. The rotor core 24, which is advantageously designed as a laminated core, also has a plurality of axially running openings, the openings being arranged at least essentially around a center point M.

6 shows the in 5 disclosed opening 11 in detail.

The opening 11 has at least one elliptical section 5 .

The elliptical section 5 is advantageously formed at an opening 11 pointing in the direction of the center M.

The figure shows an embodiment in which adjacent circular sections 7 and 8 are formed in addition to the elliptical section.

From this front view it can be seen that a cage bar 3 does not fill the entire opening 11 .

Since the opening is not filled by the cage bar 3, there is air L, for example, in the unfilled areas.

The notch has a notch surface 31 in the figure.

FIG 7 shows the rotor 21 in a front view.

The rotor 21 has a plurality of openings 11 .

The figure also shows the short-circuit ring 2 and the shaft 25.

The openings 11 preferably run axially, relating to an axis of rotation of the rotor 21, as already shown in FIG 5 shown.

In the figure, the openings 11 are arranged around a center point M, with at least one radial end of the opening 11 having an elliptically shaped section 5 .

8 shows the dynamo-electric rotary machine 23, having a rotor 21 with a shaft 25 and a rotor core 24 and a stator 22. 9 shows a method for manufacturing the rotor 21.

In a method step S1, the rotor stack is provided.

Cage bars are inserted into the axially extending openings of the rotor stack in a method step S2.

In a method step S3, at least one annular short-circuit disk 4, ...,45 is attached to cage bars 3 protruding from the rotor assembly.

In a method step S4, the short-circuit rings are connected to the cage bars in a cohesive manner, in particular by means of welding.

Alternatively, at least one further annular short-circuit disk 4, . . . 45 can be attached in a method step S5.

A cohesive connection, in particular by means of welding, of the annular short-circuit disks 4 . . . 45 to one another and to the cage bars 3 succeeds in a method step S6.

Laser welding and/or electron beam welding is advantageous here. Other types of connection, in particular other types of welding, are also conceivable.

Claims (9)

Rotor (21) for a dynamo-electric rotary machine (23), in particular an asynchronous machine, with a rotor stack (24) and a squirrel cage, the squirrel cage having a plurality of electrically conductive cage bars (3) and electrically conductive short-circuit rings (2), wherein the cage bars (3) are arranged in slots of the rotor core (24), wherein the cage bars (3) are connected to at least one short-circuit ring (2), wherein the cage bars (3) have a notched area (311). Rotor (21) according to claim 1, wherein the notched area (311) lies in an opening (11) of the short-circuit ring (2). Rotor (21) according to one of the preceding claims,
wherein a transition (310) from the notched area (311) to another area (312) of the cage bar (3) has a rounding. Rotor (21) according to claim 3,
wherein a transition (310) from the notched area (311) to the other area (312) is arcuate or in the shape of a segment of a circle. Rotor (21) according to one of the preceding claims,
wherein an end of the notched portion (311) is coplanar with an end of the short ring (2). Rotor (21) according to one of the preceding claims 3 to 5,
wherein the transition (310) is in the area of the rotor core (24). Method for manufacturing a rotor (21) according to one of claims 1 to 6, with the following steps: - Providing the rotor assembly (24), - Insertion of cage bars (3) in the axially extending openings of the rotor core (24), - Attaching at least one short-circuit ring disk (4, ..., 45) to the cage bars protruding from the rotor assembly (24), - Cohesive connection, in particular by means of welding, of the annular short-circuit disk (4, ..., 45) with the cage bars
or - Attaching at least one further short-circuit ring disk (4, ..., 45) and cohesively connecting, in particular by means of welding, the short-circuit ring disk (4, ..., 45) to one another and to the cage bars. A cage bar for a rotor according to any one of claims 1 to 7. Dynamoelectric rotary machine (23) comprising a rotor (21) according to any one of claims 1 to 7.

Images